Semimechanical telephone system



W. G. BLAUVELT.

f SEMIMECHANICAL TELEPHONE SYSTM.

APPLICATION FILED APR. H, 1917.

Patented Dec. 21', 1920.

5 SHEETS-SHEET l.

INVENTOR Wlauvelt BMMIWWM. 4 (/MaM ATTORNEY` W. G. BLAUVELT. SEMINIECHANICAL TELEPHONE SYSTEM.

APPLICATION FAILED APR.11, i911.

Patented Dec. 21, 1920.

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W. G. BLAUVELT. SEMIMECHANICAL TLEPHONE SYSTEM.

APPLICATION FILED APR. H, 1917.

Patented Dec. 21, 1920.

5 SHEETS-'SHEET 4.

www Mug@ QS W. G. BLAUVELT.

SEMIMECHANICAL TELEPHONE SYSTEM.

APPLICATION FILED APR. I. |917.

Patented Dec. 21, 41920.

5 SHEETS-SHEET 5.

WENN W .D V @QT INVENTOR S www Km o/ glfglauvelt 24h/'v KM ATTORNEYS.

UNITED STATES. PATENT orricla.`

WILLIAM G. BLAUVELT, 0F NEW YORK, N. Y., ASSIGNOR TO AMERICAN TELEPHONE .AND TELEGRAIEI-I COMPANY, A CORPORATION OEY NEWv YORK.

SEMI'MECHANICAL 'JIEJEPZPIONEy SYSTIEM-l Specification of Letterslatent.

Patente-a 13e-m21, 1920.

Application led April 11, 1917. SeriaLNo. 161,277.

T0 all whom t may concern.'

Be it known that I, WILLIAM G. BLAU- vnL'r, residing at New York, in the county of New York and State of New York, have invented certain Improvements in Semimechanical Telephone Systems, of which the following is a specification.

rllhis invention relates to semi-automatic telephone systems and more particularly concerns the provision of means whereby when an operator answers a call by inserting the plug or" an idle cord circuit into the jack oi the calling subscriber, the operators talking set and associatedl apparatus will be automatically connected with that particular cord. circuit.

It is one oi the objects of ,this invention to provide means whereby the time necessary to effect this operation shall be reduced to a minimum, and the apparatus utilizedtherefor shall be simple in construction and eilicient in operation. In constructions heretofore used, where an operator has at her disposalA a large number oicord circuits to each of which she must be able to connect her listening,` apparatus, in order to effect such connections, it has been proposed to provide a one-motion switch which rotates the terminals of the talking set into connection with the terminals leading to any one oi the cord circuits which, in la. given case, might necessitate the switch taking as many steps as there were cord circuits, the switch being provided with positions for each cordcircuit. By the present inventionthe time for making the connection isreduced by arranging the cord circuits in groups oi' a small number, with a switch for each group to select a particular cord circuit in the group, and providing a simultaneously operating switch common to the groups, to selectthe particular group and connect they operators set to. the terminals oir' the group. Suppose for instance there are twenty-four cord circuits, divided. into four oroups of six each. Four switches, preferably oi' the sequence switch type shown for instance inU. S. Patent to McBerty 1105811,-August 4, 1914, or patent to Reynolds et LZ.,.11217SO8, February 9, 1915, would be provided each having siX positions,one position Jfor each cord circuit Y of the group to which the switch isassigned. An additional switch of the same type would be provided,common. to the other fou-r, and

having, five positions, one for each of the first four switches and a fifth or listening out positionin which theT operator-s set would be connected to no cord circuit. in any group isused in answering a call, as soon. as the operator plugs in, the switch oithat group. begins to` seek that particular cord, and` simultaneously the common switch seeks the group switch. Attjhe most, this operation. will: involve only the. time necesisary for one of the switches to, make six skepis,l which wouldbe approximately onethird of a second.

The invention. may be more fully understood. by referenceto thedrawing in which Figures la, 1b, 1, 1d and. 1e when arranged so that Figs. 1b and 1c are sideby side,with Fi 1d arranged horizontally beneath them, andFig. l.EL and 1.e horizontally above them, illustrate such portionsof the circuits. as

are necessary to understand the invention.`

.Y The apparatus illustrated. inthe several sheeets which taken: together constitute Fig. 1 of the drawing comprises essentially i'our cord-selecting switch structures of the sequence switch. type under the control of motor magnetsltn R2, R3 and R, and each comprising three sets of contacts such as 20 to 24 inclusive,fwherebya set of conductors l, 2a, 3a, 4a and 5a may beV switched into,A connection with` any. one oi. six. sets of leads 1b, 2b, 3b, 4b and 5l corresponding to one of six cord circuits, the cord circuit selected depending upon which one of six positions the switch. assumes. The switch has no normal position but may rest with its contacts in position to select any one of the six cord circuits. Another switch of the same general type, and under the control oi' motor magnet R5, is provided with two sets of contacts such as 26 to.. 29 inclusive which operate to switch leads 1, 2, 3' and 4 from the operators talking. set into connectioniwith one of four sets of leads la, 2n, 3a, 4EL extending to the Jfour switches` controlled by. magnets l?; Bwg and R4.. This switch has five positions, four of which are utilized in selecting one of the four cord selecting switches, and the fifth of which is a listening out positionl in which the talking set isdisconnected from vall of the cord circuits. This switch has no normal position, but is ordi narily in the listening out position. All of the switches are provided with additional When a cord.

controlling contacts the purpose of which will be clear from a detailed statement of the operation hereinafter given.

Associated with each cord circuit such as shown in Figlia is a sequence switch under control of a motor magnet R. y The contacts of this switch are not shown together upon the drawing7 but are variously located in order to simplify the diagram. Only the sequencev switch contacts yshown in Fig. l are under the control of this sequence switch R. The function of this switch is to control the sequence of operation whereby the sender is selected and the sending operation performed, but as these features have nothing to do with the present invention only such features of the operation of the district sequence switch R as are concerned with the present invention will be herein referred to. But one cord circuit is shown in the diagram, it being understood that the other cord circuits are connected to the cord selecting switches by leads similar to 1b to 5b inclusive which are controlled by contacts as indicated in Figs. l and lc of the drawing.

lVith this general description in mind, the invention will be clear from a statement of the operation of the apparatus it being understood that for any cord circuit the lead corresponding to lead 5l is always grounded except when the operator is listening in. Thus the lead 5b 0f the cord i shown in Fig. la is 'grounded in positions 2 to 6 of selecting switch R1 over upper contact 20. Cord circuit #l is selected in position l of this switch, in which position lead 5b is connected over lower contact 20 to conductor 5fL which is grounded over spring 25 in positions 2 to 5 of group selecting switch R5. In the first position of this switch, which is the position in which the operators set is connected to leads R-l-f, contact 25 is open. Thus it will be seen that only when switches R1 and R5 are both inthe first position, will lead 5b be ungronnded, the operators set being connected to cord circuit .lt/:l in this position.

The operation will now be described for cord circuit #l it being understood that the operation 'for the other cords will vbe similar.

Plugging in.

Assuming that in answer to a call the op- .f erator inserts the plug. P of cord circuit :ttl into the ack of the calling line, relay 30 will be energized over the grounded third contact of the liaclr (not shown) and in closing its front contacts 31 and 32 will apply ground to a pair of terminals 33 and 34 connected to finders controlled by motor magnets R1 and R5. The circuit for R1. is as follows assuming the switch controlled 1thereby to be in a position other than the rst:

From battery through motor magnet R1 over contact 35 to termina-l 34, contact 32, sequence switch contact 36 in position 1 to ground.

The circuit for R5 assuming this finder to be in any position other than the first is as follows:

From battery, winding of motor magnet R5, lower contact 37, terminal 33, sequence switch contact 45, contact 3l of relay 30, lead 5" upper contact 20 to ground if finder R1 is not in position 1, but if it should happen to be in position 1, the circuit would continue over lower contact 20, lead 5a, contact 25 to ground.

Upon the closure of these two circuits switches R, and R5 rotate simultaneously to select the used cord circuit :,ttl. As soon as lll reaches its iirst position the former circuit will be opened at contact 35 and the switch will come to rest. If has not yet reached its first position the second circuit will be continued over lower contact 2O to ground instead of upper contact 20,' and R5 will continue to rotate until it reaches first position, whereupon its circuit will be opened at contact 37 and the switch will come to rest, leads l, 2, 3 and l being connected over contacts 26-29 of finder R5 in ,"irst position to leads la to la inclusive which in turn are connected over contacts 2li- 2li of finder R1 to leads 11 to 4b of cord circuit #-1.

rit the samel time the circuits for motor magnets R1 and R5 were closed, relays 38 and 39 in parallel thereto were energized and by means of their contacts held open a ground lead 40, These relays being both denergized upon switches R1 and R5 coming to rest, ground lead 40 is closed and a circuit is completed for sequence switch m0- tor magnet R from battery, winding of said magnet, upper contact 4l, lead 4b, lower contact 2l, lead 4ta, contact 26, lead i through the operators keys to lead 40 and serially through normally closed contacts of the relays associated with motor magnets R1 to R5 inclusive to ground, driving se quence switch R from position l to position 2, when a sender is associated with the cord circuit as follows: i

l'Vith sequence switch R in position 2 a circuit is closed from ground, over back contact of armature 48 of relay 46, upper sequence switch contact 54, sequence switch contact 67, winding of motor magnet 68 to battery, driving the sequence switch conlos over a circuit from ground, back contact of armature 48, contact 55, contact 72, wiper 71, contact 73, winding of relay 65 to battery. Relay 65 opens the circuit of motor magnet so that the finder comes to rest and a sender, conventionally indicated at 74 is associated with the cord over wipers 75 and 76. Test relay 65 at its front contact closes a circuit over contact 84 which drives the motor magnet 68 of the sequence switch out of position 2 into position 5, whereupon the sequence switch contact 73 is shifted to its lower position and test relay 65 is maintained energized over lower contact 73, winding of relay 85, contact 86 of the sender sequence switch, wiper 77, contact 78, contact 64, back Contact of armature 48 to ground. Relay 85 is now energized. and locks itself over contact 87 and at the front contact of armature 88 closes a circuit over contact 89 of the sender sequence switch, through the winding of the motor magnet 90 of said switch, `driving the latter into p0- sition 2. rllhe operator in setting up the call upon her keyboard closes. a contact 91 which completes the energizing circuit of motor magnet 90 over contact 92, driving the sender sequence switch to position 3, whereupon Contact 93 is closed so that the sender conventionally indicated at 74 is vconnected to the cord, and proceeds to operate the switching machinery (not shown) inV accordance with the call set up on the keyboard.

The operators talking set is now bridged across the cord circuit over conductors 2-43, lower contacts 27 and 28, 28-32 lower contacts 22 and 23, and 2b-3b, so that she can ascertainthe number desired by the calling subscriber, and at the same time the ring back keys 60, the coin return key 61, the master listening out key 62 and master restoring key 63 become effective. Should the operator depress one of the ring back Areys, battery would be applied over its right hand spring to conductor 4 and over contact 26, lead 4a, contact 21,` lead 4b, cord cut-oii relay 42, upper sequence spring 43 in position 2 to ground, while ringing current would be applied through the other two springs of the ring back key and over conductors 2 3 to the answering end of the cord circuit. Thus the answering end of the cord is cut ofi and ringing current applied thereover ato ring out on the calling line. The operation of the coin return key is similar.

Us@ of muster listening ont ccy, sequence .switch R not being-in Position 2.

lf the operator uses the master listening with the district sequence switchI in any other position, a circuit is closed `through set to the latter cord, thus disconnecting it from the first cord.

Listening in by use of a listening in key.

Associated with each cord circuit is a listening key 94 (see Fig. 1a). Should the op,- operator desire to listen in on a connection in which the district sequence switch is in a position other than position 18, which will be described later, she presses the key 94 of the cord in question. This. manually grounds the terminals 33 and 34 of the cord in question and starts the group finder R5 and the cord finder R1, R2, or R1 as the case may be, over circuits similar to those described inconnection with energization of relay 30 upon plugging into a calling line, and the same sequence of operations results as already described, under the heading Plugging in. Y Listening ont, sequence switch R being in Position 2.

If after answering a call the operator desires to leave the plug of the cord in the jack without completing a connection, as where a subscriber has forgotten the number desired and the operator wishes in the meantime to answer other calls, it is desirable that the sender should be released from that cord in order not to keep it idle uselessly, as would be the case if the district sequence switch R of the cord were permitted to remain in position 2. Therefore, with the `district sequence switch in this position, should the operator listen out as described under heading Use of master listening out key, R not being in Position 2,7 either by plugging in with another cord or by pressing the master listening out key 62, a ground is applied to lead 5b at contact25 or contact 20 and current fiows fromA ground over lead 5b, front Contact 31 of relay 30, lower sequence switch contact45, winding of relay 46 and battery to ground. Relay 46 is energized and locks itself over its contact 47 and sequence switchY contact 43. This locking circuit is maintained from position 2 to position'10, so that relay 46 over its contact 48-and sequence switch contact 49 closes thc energizing circuit. ofthe motormagnet R to drive the switch controlled Vthereby to position 4. In position 4 relay 53 is ener-V gized over a circuit from battery, contact 52 ot relay 46, relay 53, contact 54 to ground, thereby closing a circuit for R from battery, winding of R, lower contact 41, contact ot relay 53, contact 55 to ground. The sequence switch is then driven to position 6 through position 5 under control of master Contact 58, in which position the circuit over contact 48 of relay 46 drives it to position 7. In position i the circuit controlled by relay 53 drives the switch controlled by motor magnet R to position 8 from which it passes to position 14 under joint control ot master Contact 58 and contact 48 of relay 46. In position 14 a circuit for R is closed over the back contact of a relay 50 in the calling end otl the cord circuit, sequence switch contact 51, winding of motor magnet R to battery, driving R into position 17. In position 1T relay 46 is energized by a circuit over lower contact 43, and closes a circuit from battery over its contact 52, winding of relay 53, contact 54 to ground. Relay 53 is therefore energized and closes a circuit for R from battery, winding of motor magnet R, lower contact 41, contact ot relay 53, sequence switch contact 55 to ground, driving R into position 18. As soon as the Sequence switch left position 6 the sender was released as follows: The leads to the sender are opened at contacts 79 and 8O and the holding circuit of relays 65 and 85 is opened at contact 64. Relay 65 in denergizing, at its back contact closes a circuit over lower contact 69 for motor magnet 68 driving the cord finder sequence switch through position 1 8 into position 1. Relay 85 at the same time de'energizes and at the back contact of armature 88 closes a circuit for motor magnet 9'() over lower contact 89 driving the sender sequence switch through position 18 to position 1 and restoring the sender to normal. Contact 93 ofthe sender is now open and although the wipers 75 and 76 of the finder are allowed to rest on the contacts 94 and 95 leading to the cord circuit, until such time as another cord is taken for use and a sender associated therewith, the sender is no longer associated with the cord by reason oi' the fact that contacts 7 9 and 8() were opened as the sequence switch R passed out ot position 6.

Listening in, R being in .78.

I It now the operator desired to return tol a connection left in the condition just described, it is desirable that a sender be picked up again in order that the operator may set up a call. It, therefore, the operator pushes the listening key 94 individual to a cord, R being in position 18, ground is applied to terminals 33 and 34, causing the finders to hunt for the cord as already described.` lhen the finders stop and ground lead 40 is closed, thereby applying ground to lead `4, a circuit for R is closed from ground over leads 4, 4*", 4b upper sequence switch contact 41 closed in position 18, winding of motor magnet R to battery, driving R through positionl into position 2 so that the listening set is connected to the cord and a sender is associated therewith in a manner already set forth.

Use of the .master restoring hey.

It, with the district sequence switch between positions 2 to 6 inclusive, the operator presses the master restoring key 63, she places a ground on lead #l and a circuit or relay 46 is closed over leads 1, 1a, 1b, contact 56, winding of relay 46 to battery. Relay 46 is locked up and closes a circuit which drives R to position 18 in a manner already described under heading Listening out, R being in 2. In position 18, the operators set being at this time connected to the cord, lead 4b is grounded over ground connection 40, and a circuit is closed over ground lead 4b, upper sequence switch contact 41, motor magnet R to battery, driving R through position 1 into position 2. As R passed out of position 6 on its way to 18 he sender was released in a manner already described. In position 2 a sender is again associated with the cord as ydescribed under heading Plugging in and the apparatus is ready for setting up a call. The restoring key 63 is only effective in positions 2-6, as contact 56 is open in all other positions.

Wit/drawing the plug 'while the operators @et is disconnected from the cowl.

while listening out the operator withdraws the plug, relay 30 is'denergized and a circuit is closed over lead 5b, (which is always grounded except when listening in), r contact 31 of relay 30, lower contact (ii the district switch is between positions 2 to 6 inclusive) relay 46 to battery. Relay 46 is locked up and closes a circuit to drive switch R to position 18 as already described. In position 18 the ground connection extends over upper contact 57 to motor magnet R, driving the switch into iinst position. lf the district switch had been beyond position 7, the ground connection would pass over upper contact 57 to motor magnet R without energizing relay 46, thus driving the switch to position 1.

llfithfZra/wing a ping with the ope/intents' set connected.

1t while listenin in on a cord the o 3eratorremoves the plug from the ack, relayv isting connections.

It will thus be seenthat a very simplev and yet eilicient means has been devised whereby automatic listening in is effected without appreciable loss of time, and while the invention is disclosed as embodied in a particular form, it will be understood that it is capable .of a wide variation in embodiment without departing -rom the spirit of the invention as defined in the appended claims.

lVhat I claim is:

l. In a telephone system a plurality of answeringcord circuits divided into groups, an operator7s telephone setcommon to all `ci the `cord circuits, 4means associated with 'the operators telephone set to select a group, and means to simultaneously select a `cord in a group, whereby said operators -telephone set is connected to a cord circuit.

2. In a telephone system, a plurality of cord circuits divided into groups, an operatorstelephone set commento all of the cord circuits, group selecting means associated with the operators telephone set, cord selccting means for each group, means associated with each cord circuit operating to cause saidggroup selecting means and said cord selecting means to operate simultaneously to switch the operatorie telephone set into connection with the cord circuit.

3. In a telephone system, ya plurality cord circuits divided into groups, an operators set common to all of lthe 'cord circuits` a switching means foreach group adapted to select any cord in its group, a switching means associated with the operators set, and adapted to select a group of cord circuits, said switching means having a position for each group and an additional listening out position, means associated with each cord operating @to cause the cord selecting means associated with the group in which a 'cord is located to select ysuch cord and to simultaneously cause `vthe `grou-p selecting means to select the group, whereby the operator may listen in on such cord, and means to move the group selecting means to its listening out position, whereby the operator is prevented from listening in on any cord.

4. In a telephone system, answering jacks, a plurality of cord circuits divided into groups, an operators telephone set common to all of the cord circuits, group selecting means associated with the operators telephone set, cord selecting means for each group, means operative upon plugging a cord into an answering jack to cause said group selecting means and said cord selecting means to operate simultaneously to switch the operators telephone set into connection with the cord circuit.

5. In a telephone system, a plurality ot cord circuits divided into groups, keys associated with each cord circuit, an operators telephone set common to all of the cord cir-- cuits, group selecting means associated with the operators telephone set, cord selecting -vmeans tor each `group. and means operative upon the depression of a key associated with a cord circuit to cause said group selecting means and said cord selecting means to operate simultaneously to switch the operators telephone set into connection with such cord circuit.

G. In a telephone system, answering jacks, a :plurality of cord circuits divided into groups, anoperators telephone set common to all of the cord circuits, group selecting lleans associated with the loperators telephone set, cord. selecting means for each group, means operative upon plugging a cord into an answering jack to cause said group selecting means and said cord selecting means to operate simultaneously to switch the operators telephone set into conn ation with the cord circuit, and means operative upon plugging a second cord into a calling jack to cause said switching .means to disconnect vthe operators `telephone set from the iirst cord and connect it to the second.

7. In a telephone system, a plurality of cord circuits, an operators set common to all yof the cord circuits. selective means operating to select an individual one of said cord circuits and connect the operators set thereto, a sender, means to associate the sender with the selected cord circuit, means to disconnect the operators set from the selected cord circuit, and means operative upon such disconnection to vrelease the sender.

S. In a telephone system, a plurality of cord circuits, an operators set common to all of the cord circuits, a sequence switch individual to each of the cord circuits, means operative when said switch is in normal position -to select an individual one ot said cord circuits and connect the operators set thereto, means responsive to the selection of a cord to move said sequence switch into an off-normal position, a sender, means operative im such yolli-normal position of the sequence switch to associate the sender with the selected cord circuit, and means also operative in such off-normal position of the sequence switch to disconnect the operators set from the selected cord circuit and simultaneously release the sender.

9. In a telephone system, a plurality of cord circuits, an operators set common to all ot the cord circuits, a sequence switch individual to each of the cord circuits, means operative when said switch is in normal position to select an individual one of said cord circuits and connect an operators set thereto, means responsive to the selection of a cord to move said sequence switch into an olfnormal position of the sequence switch to associate the sender with the selected cord circuit, means whereby the sequence switch may assume other olf-normal positions, and

means operative if the sequence switch is in the iirst off-normal position to disconnect the operators set from the selected cord and at the same time release the sender, said means operating if the sequence switch is in another position to disconnect the operators set Without releasing the sender.

10. In a telephone system, a plurality of cord circuits, an operators set common to all of the cord circuits, selective means operating to select an individual one of said cord circuits and connect the operators set thereto so that an operator may listen in. on such cord circuit, a sender, means to associate the sender with the selected cord circuit, means whereby an operator while listening in may restore a set up connection and prepare the apparatus associated with a cord circuit for the setting up of a new connection.

11. In a telephone system, answering jacks, a plurality of cord circuits divided into groups, an operators set common to all of the cord circuits, group selecting means associated with the operators set, cord selecting means for each group, means operative upon plugging a cord into an answering jack to cause said group selecting means and said cord selecting means to operate simultaneously to switch the operators set into connection with the cord circuit, means to disconnect the operators set, and means operative when the plug is withdrawn while the operators set is disconnected, to restore the cord circuit to normal, but ineffective it the plug is withdrawn while the operators 'set is connected.

12. In a telephone system, a plurality of cord circuits divided into groups, an operators ringback and coin control keys common to all of the cord circuits, means associated with the operators keys to select a group and means to select a cord in a group, whereby said operators keys are connected to a cord circuit.

13. In a telephone system, 4a plurality of cord circuits, an operators set'common 'to cord circuits and connect an operators set thereto, means responsive to the selection of a cord to move said sequence switch into an oit-normal position, a sender, means operative in such off-normal position of the sequence switch to associate the sender with the selected cord circuit, means whereby the sequence switch may assume other oit-normal positions, means operative if the sequence switch is in the first oienormal position to disconnect the operators set from the selected cord vand at the same time release lthe sender, said means operating 'it the sequence switch is in another position to disconnect the operators set without releasing the sender, and means under the control of the operator after the sender has been released to cause the sequence switch to assume its first oit-normal position whereby a sender is again associated with the cord circuit.

14. In a telephone system, a plurality of cord circuits divided intoY groups, an operators telephone set common to all of the cord circuits, group selecting means associated with the operators telephone set, cord selecting means for each group, means controllable at will to cause said group selecting means and said cord selecting means to operate to switch theoperators telephone set into connection with a cord circuit, and means controllable at will to cause said switching means to disconnect the operators telephone set from the first cord and connect it to the second.

In testimony whereof, I have signed my name to this specification in the presence of Y two'subscribing witnesses, this third day of April, 1917.

WILLIAM G. BLAUVELT. Witnesses:

I-I. M. BAsooM, EDWARD C. MOLINA. 

